Can I Put Orange in Compost?

Carbon Ratio

• All compost piles require a good carbon to nitrogen ratio to encourage the growth of composting organisms. Most compost piles need a carbon to nitrogen ratio of 30 parts carbon to 1 part nitrogen. Most fruit waste, including citrus, is about 35 parts carbon to 1 part nitrogen. If you intend to compost citrus and other high carbon materials, reduce the amount of grass, leaves and other yard waste you add to the pile. More food waste will increase the amount of nitrogen in the compost, creating better conditions for bacteria, fungi and other decomposers.

Acid

• Citrus fruits and their peels have relatively high acid content, which can disrupt your compost pile's decomposing action. High acid environments are also disruptive to worms, both in conventional compost piles and vermicomposting. If you need to compost oranges, do so in moderation, adding only a few peels at a time. Avoid adding other high-acid materials at the same time.

Toxicity

• Oranges and other citrus fruits contain a substance called d-limonene. This antiseptic chemical is located mostly in the fresh peel of the fruit, and decomposes over time. It also works as an insect repellent and insecticide when used in large quantities. Composting lots of orange peel could irritate or sicken beneficial invertebrates, including earthworms. As with acid levels, avoid composting large amounts of orange peel at a time to keep your compost pile healthy.

Considerations

• The acid and d-limonene in citrus peels breaks down over time. Leaving citrus peels out of your main compost pile or bin to decay separately can allow you to compost greater quantities of citrus. According to Compost This, once the citrus peel has developed green or gray furry mold, most of the problem substances have decayed, making the orange peel easier for your compost pile to deal with.